Non-volatile memory devices as represented by NAND type flash memory are manufactured using semiconductor wafer processes. Also, the increase in capacity, the reduction in power consumption, and the reduction in cost have been achieved by progress in 2-dimensional microfabrication technology for wafer processes. However, massive equipment investment is required for further progress in microfabrication technology. Therefore, the development of memory devices with a 3-dimensional memory cell unit in which a plurality of memory layers is stacked is progressing.